In image processing, it is possible to suitably reduce density unevenness and graininess according to the ink used in printing. More specifically, when dividing multi-valued data and generating data for 2-pass multi-pass printing, in addition to divided multi-valued data for each of the two passes, divided multi-valued data that is common to the two passes is also generated. Moreover, quantized data of that common multi-valued data is reflected on the quantized data for each of the passes. Furthermore, when generating the quantized data, the division ratios used when generating the common data using the aforementioned multi-valued data division are set according to the colors of ink used in printing. By doing so, it becomes possible to suitably reduce density unevenness and graininess according to the colors used in printing.
Legal claims defining the scope of protection, as filed with the USPTO.
1. An image processing apparatus that, for printing an image on a predetermined area of a printing medium by performing a plurality of relative scans between a printing unit for ejecting inks of a plurality of colors and the printing medium, processes multi-valued image data that corresponds to the image to be printed on the predetermined area, said apparatus comprising: a generating unit configured to generate respective multi-valued data that correspond to each of the plurality of relative scans and multi-valued data that corresponds commonly to at least two relative scans among the plurality of relative scans, by dividing the multi-valued image data according to division ratios according to an ink color that corresponds to the multi-valued image data; a quantization unit configured to perform quantization processing for each of the multi-valued data generated by said generating unit to generate respective quantized data that correspond to each of the plurality of relative scans and quantized data that corresponds commonly to the at least two relative scans among the plurality of relative scans; and a combination unit configured to combine the quantized data generated by said quantization unit for each corresponding relative scan to generate combined quantized data that corresponds to each of the plurality of relative scans.
2. The image processing apparatus according to claim 1 , wherein said generating unit divides the multi-valued image data according to the division ratios, which make a percentage of a value of the multi-valued data corresponding commonly to the at least two relative scans with respect to a value of the multi-valued image data smaller in the case that the ink color corresponding to the multi-valued image data is a first ink color than that in the case that the ink color corresponding to the multi-valued image data is a second ink color having lower lightness than the first ink color.
3. A non-transitory readable storage medium storing a program that makes a computer function as an image processing apparatus according to claim 1 .
4. The image processing apparatus according to claim 1 , wherein the quantization unit performs the quantization processing for each of the multi-valued data by a dither method using a dither matrix.
5. The image processing apparatus according to claim 4 , wherein the respective dither matrices used in the quantization processing by dither method for respective multi-valued data that correspond to the plurality of relative scans and the dither matrix used in the quantization processing by dither method for multi-valued data that corresponds commonly to at least two relative scans among the plurality of relative scans are different from one another.
6. The image processing apparatus according to claim 1 , wherein the quantization unit performs the quantization processing for each of the multi-valued data by an error diffusion method.
7. The image processing apparatus according to claim 6 , wherein respective error diffusion matrices for diffusing errors caused when processing an object pixel, which is used in the quantization processing by the error diffusion method for respective multi-valued data that correspond to the plurality of relative scans and an error diffusion matrix used in the quantization processing by the error diffusion method for multi-valued data that corresponds commonly to at least two relative scans among the plurality of relative scans are different from one another.
8. The image processing apparatus according to claim 1 , wherein the combination unit is configured to combine another of the respective quantized data that corresponds to another of the plurality of relative scans and the common quantized data generated by said quantization unit to generate combined quantized data that corresponds to the another of the plurality of relative scans.
9. The image processing apparatus according to claim 1 , further comprising an ejection controlling unit configured to control an ejection of ink in the one of the plurality of relative scans according to the combined quantized data that corresponds to the one of the plurality of relative scans.
10. An image processing method of, for printing an image on a predetermined area of a printing medium by performing a plurality of relative scans between a printing unit for ejecting inks of a plurality of colors and the printing medium, processing multi-valued image data that corresponds to the image to be printed on the predetermined area, said method comprising: a selecting step of selecting a second processing mode in the case that an ink color corresponding to the multi-valued image data is a first ink color and select a first processing mode in the case that an ink color corresponding to the multi-valued image data is a second ink color having lower lightness than the first ink color; and a processing step of performing the processing mode selected by said selecting step, wherein the first processing mode is a mode that performs an image processing including (A) a first division process for dividing the multi-valued image data into respective multi-valued data that correspond to each of the plurality of relative scans and multi-valued data that corresponds commonly to at least two relative scans among the plurality of relative scans, (B) a first quantization process for quantizing each of the multi-valued data obtained by the first division process to generate respective quantized data that correspond to each of the plurality of relative scans and quantized data that corresponds commonly to the at least two relative scans among the plurality of relative scans, and (C) a combination process for combining the quantized data generated by the first quantization process for each corresponding relative scan to generate combined quantized data that corresponds to each of the plurality of relative scans, and the second processing mode is a mode that performs an image processing including (D) a second quantization process for quantizing the multi-valued data to generate quantized data, and (E) a second division process for dividing the quantized data generated by the second quantization process into respective divided quantized data that correspond to each of the plurality of relative scans.
11. An image processing method of, for printing an image on a predetermined area of a printing medium by performing a plurality of relative scans between a printing unit for ejecting inks of a plurality of colors and the printing medium, processing multi-valued image data that corresponds to the image to be printed on the predetermined area, said method comprising: a generating step of generating respective multi-valued data that correspond to each of the plurality of relative scans and multi-valued data that corresponds commonly to at least two relative scans among the plurality of relative scans, by dividing the multi-valued image data according to division ratios according to an ink color; a quantization step of performing quantization processing for each of the multi-valued data generated by said generating step to generate respective quantized data that correspond to each of the plurality of relative scans and quantized data that corresponds commonly to the at least two relative scans among the plurality of relative scans; and a combination step of combining one of the respective quantized data that corresponds to one of the plurality of relative scans and the common quantized data generated by said quantization step to generate combined quantized data that corresponds to the one of the plurality of relative scans.
12. The image processing method according to claim 11 , wherein the quantization step performs the quantization processing for each of the multi-valued data by a dither method using a dither matrix.
13. The image processing method according to claim 12 , wherein the respective dither matrices used in the quantization processing by dither method for respective multi-valued data that correspond to the plurality of relative scans and the dither matrix used in the quantization processing by dither method for multi-valued data that corresponds commonly to at least two relative scans among the plurality of relative scans are different from one another.
14. The image processing method according to claim 11 , wherein the quantization step performs the quantization processing for each of the multi-valued data by an error diffusion method.
15. The image processing method according to claim 14 , wherein respective error diffusion matrices for diffusing errors caused when processing an object pixel, which is used in the quantization processing by the error diffusion method for respective multi-valued data that correspond to the plurality of relative scans and an error diffusion matrix used in the quantization processing by the error diffusion method for multi-valued data that corresponds commonly to at least two relative scans among the plurality of relative scans are different from one another.
16. An image processing apparatus that, for printing an image on a predetermined area of a printing medium by performing a plurality of relative scans between a plurality of printing units for ejecting inks of different colors and the printing medium, processes multi-valued image data that corresponds to the image to be printed on the predetermined area, said apparatus comprising: a detection unit configured to detect ink color of the printing unit used in printing; a duty detection unit configured to detect printing duty based on the multi- valued image data corresponding to the ink color detected by said detection unit; a division unit configured to divide the multi-valued image data corresponding to the detected ink color into respective multi-valued data that correspond to each of the plurality of relative scans and multi-valued data that corresponds commonly to at least two relative scans among the plurality of relative scans, according to division ratios according to the detected ink color and the detected printing duty; a quantization unit configured to perform quantization processing for each of the multi-valued data generated by said division unit to generate respective quantized data that correspond to each of the plurality of relative scans and common quantized data that corresponds commonly to the at least two relative scans among the plurality of relative scans; and a combination unit configured to combine one of the respective quantized data that corresponds to one of the plurality of relative scans and the common quantized data generated by said quantization unit to generate combined quantized data that corresponds to the one of the plurality of relative scans.
17. An image processing method of, for printing an image on a predetermined area of a printing medium by performing a plurality of relative scans between a printing unit for ejecting inks of a plurality of colors and the printing medium, processing multi-valued image data that corresponds to the image to be printed on the predetermined area, said method comprising: a selecting step of selecting a second processing mode in the case that an ink color corresponding to the multi-valued image data is a first ink color and select a first processing mode in the case that an ink color corresponding to the multi-valued image data is a second ink color having lower lightness than the first ink color; and a processing step of performing the processing mode selected by said selecting step, wherein the first processing mode is a mode that performs an image processing including (A) a first division process for dividing the multi-valued image data into respective multi-valued data that correspond to each of the plurality of relative scans and multi-valued data that corresponds commonly to at least two relative scans among the plurality of relative scans, (B) a first quantization process for quantizing each of the multi- valued data obtained by the first division process to generate respective quantized data that correspond to each of the plurality of relative scans and common quantized data that corresponds commonly to the at least two relative scans among the plurality of relative scans, and (C) a combination process for combining one of the respective quantized data that corresponds to one of the plurality of relative scans and the common quantized data generated by the first quantization process to generate combined quantized data that corresponds to the one of the plurality of relative scans, and the second processing mode is a mode that performs an image processing including (D) a second quantization process for quantizing the multi-valued data to generate quantized data, and (E) a second division process for dividing the quantized data generated by the second quantization process into respective divided quantized data that correspond to each of the plurality of relative scans.
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November 29, 2010
December 17, 2013
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